81569495347 has 4 divisors (see below), whose sum is σ = 81590165496. Its totient is φ = 81548825200.

The previous prime is 81569495339. The next prime is 81569495383. The reversal of 81569495347 is 74359496518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74359496518 = 2 ⋅37179748259.

It is a cyclic number.

It is not a de Polignac number, because 81569495347 - 2³ = 81569495339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81569495317) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10329154 + ... + 10337047.

It is an arithmetic number, because the mean of its divisors is an integer number (20397541374).

Almost surely, 2^81569495347 is an apocalyptic number.

81569495347 is a deficient number, since it is larger than the sum of its proper divisors (20670149).

81569495347 is a wasteful number, since it uses less digits than its factorization.

81569495347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20670148.

The product of its digits is 32659200, while the sum is 61.

The spelling of 81569495347 in words is "eighty-one billion, five hundred sixty-nine million, four hundred ninety-five thousand, three hundred forty-seven".